| ??? 02/10/07 01:57 Read: times |
#132450 - . Responding to: ???'s previous message |
the easy part 1) To write set of equations required to do address=>byte function is not at all hard. Simple table [address|content] and you're off. the not so easy part 2) To write automated minimisation process (Quinne McClusky for example) is a little harder but attainable. If you are familiar with the method it can take a few hours, if you have to get familiar a day or so. I'm starting to like that idea. I researched methods on the internet and came across Quinne McClusky, and so far, I seem to be getting some success with it. I am now going to search for a proper example of the method so that I can get my Qbasic program (for quinne McClusky) working, and then I don't have to spend hours figuring out the logic reduction in my head. Based on size of ROM (more than handful of bytes) you'll get pretty large combination net. To accommodate average bootloader you can get enormous net in number and dimensional sense! Yes, but this hardwired rom won't be that large, since I'm using up to 64 bytes of code. 5) ANY error whatsoever that is hardware-coded is IMPOSIBLE to overcome easily, so ANY error WILL cost you dearly. That is true, and I can see costs rise if the rom size is large. Since mine will be a small size, the costs won't be drastic upon mistakes. Also, I am familiar with the 8051 instructions. 6) ANY change of code (new functionality for example) is, again, IMPOSIBLE. I agree. Since this hard-code is mainly used to program an eeprom, I don't have to worry about changing the primary code. Possible more appropriate solutions: 1) ROM/... Why avoid some kind of ROM? It DOES address=>content function. It IS it's function, or am I completely wrong here? I still fail to see why you opt to use logic-gate-hardware instead od ROM? Because I want to be able to program my EEPROM on the same circuit board as my 80C51 chip is on, and I don't want to move any components when I switch from programming mode to run-time mode. 2) FPGA as mentioned and you'll get your function. Even if you are not familiar with, it can be beneficial to acquaint yourself with it since it has very versatile usage. I'm not familiar with FPGA. If it requires data to be written to it in order to function, then I won't use it. Both methods give you easy code=>hardware transitions and (usually) can be reprogrammed if anything goes wrong or if you want to improve your circuit. but I want to be able to program my system containing an 80C51BH, 32K EEPROM (28C256), and 8K SRAM without removing the chips. If I make a hardware rom, then I will be guaranteed that the code will execute all the time. |
